What three threats does Bob Ewell allegedly make against some Maycomb townspeople?

Not only is Bob Ewell’s creepy presence enough to make
many people careful around him, he also makes some threats after the trial.  He is heard
saying, “One down, two to go,” when he learns of Tom’s death; this implies that now that
Tom Robinson is out of the way, he will go after two more people.  As readers, we assume
that he will carry out some vengeance against Atticus, Heck Tate, or Judge Taylor
because of how they disgraced him during the trial.  However, Atticus, Heck, and the
Judge are powerful men, and if we know anything about Bob Ewell, we know that he is a
coward who preys on the weak.  He abuses his children and blames others for his
misfortunes.  Atticus does seem to be somewhat alarmed enough by Bob Ewell and the
sentiment of many in the community that he asks Aunt Alexandra to come stay with the
children during the trial. 

After the trial, Bob Ewell also
threatens Helen Robinson by stalking her and cussing at her.  In addition, he tries to
break into Judge Taylor’s back door one night, and he spits in Atticus’
face.

In the end, we know that the “two” he was after were
Scout and Jem.  Bob Ewell is not man enough to confront Atticus and instead seeks
revenge against Atticus through his weak and innocent children.